Passive waveguide structures and integrated detection and/or imaging systems incorporating the same

ABSTRACT

Passive components adapted for integration with at least one active semiconductor device, in an embodiment, comprise at least one metallic structure dimensioned and arranged to absorb and/or reflect a major fraction of incident electromagnetic radiation received at one or more wavelengths of a first group of wavelengths. This prevents radiation within the first group of wavelengths from being received and/or processed by the at least one active device. In an embodiment, one or more metallic structures are dimensioned and arranged to direct an amount of incident radiation, received at one or more wavelengths of a second group of wavelengths, sufficient to enable receiving or processing of incident radiation within the second group of wavelengths by the at least one active semiconductor device. In some embodiments, the passive component comprises a passive optical filter for use in spectroscopic applications, and the active semiconductor device is a detector or sensor.

REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to ProvisionalApplication Ser. No. 61/915,650 filed on Dec. 13, 2013 and entitledINTEGRATED CMOS ON-CHIP FLUORESCENCE BIO-SENSOR AND MICROSCOPY SYSTEM.

BACKGROUND OF THE INVENTION Field of the Invention

Conventional detection and/or imaging systems are used to detect, senseand/or measure properties of light over a portion of the electromagneticspectrum. A spectrometer, for example, typically includes a source ofelectromagnetic energy as well as a collimating lens structure andoptical filter configured to disperse the light to electronicphotodetectors such as a CMOS active pixel sensor array, an array ofphotodiodes, or charge-coupled devices (CCDs).

Optical spectroscopic systems are used to detect and quantify thecharacteristics or concentration of a physical, chemical, or biologicaltarget object. Medical diagnostic machines using optical spectroscopicsystems can identify pathogens and chemicals in bodily fluids, as welltrack associated enzymes, proteins, and other physiological responses tosuch items, using only minute samples of blood, urine, saliva, or thelike. Heretofore, however, the expense, size and complexity associatedwith conventional optical spectroscopic systems have impeded theirwidespread deployment. This, only those laboratory facilities havingelaborate testing protocols and specially trained technicians are ableto analyze specimens using such machines. As a consequence, the timerequired to deliver samples to the lab, the costs associated withshipping, and the handling procedures designed to avoidmisidentification and/or contamination, have further limited the rangeof diagnostic options available to medical practitioners.

A continuing need therefore exists for detecting and/or imaging systemswhich are efficient, easy to use, and relatively inexpensive tofabricate and maintain.

SUMMARY OF THE INVENTION

The Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

A passive component according to one or more embodiments is adapted forintegration with at least one active semiconductor device. The passivecomponent comprises at least one metallic structure dimensioned andarranged to absorb and/or reflect a major fraction of incidentelectromagnetic radiation received at one or more wavelengths of a firstgroup of wavelengths, so as to prevent such major fraction of incidentradiation from being one of received or processed by the at least oneactive device. Alternatively, or in addition, the at least one metallicstructure is dimensioned and arranged to direct an amount of incidentradiation, received at one or more wavelengths of a second group ofwavelengths, sufficient to enable receiving or processing of incidentradiation, within the second group of wavelengths, by the at least oneactive device.

A detection and/or sensing system according to one or more embodimentscomprises at least one active component defined on a first substrate,the at least one active component comprising a semiconductor devicedimensioned and arranged to at least one of detect or process radiationincident thereon. The system further comprises at least one passivecomponent defined on a substrate, the at least one passive componentincluding one or more metallic structures dimensioned and arranged to atleast one of absorb or reflect a major fraction of incident radiation,the incident radiation received at one or more wavelengths of a firstgroup of wavelengths, so as to prevent such major fraction of incidentradiation from being one of received or processed by the at least oneactive component. Alternatively, or in addition, the at least onemetallic structure is dimensioned and arranged to direct an amount ofincident radiation, received at one or more wavelengths of a secondgroup of wavelengths, sufficient to enable receiving or processing ofincident radiation, within the second group of wavelengths, by the atleast one active component.

According to one or more embodiments, the at least one metallicstructure comprises a waveguide array filter, a grating array filter, ora meta material filter. In some embodiments, the at least one metallicstructure alternatively or additionally includes a metallic lensstructure formed from a plurality of metallic segments or rings definedin one or more layers of dielectic materials.

A monolithically integrated fluorescence detection system, comprising: asubstrate of semiconductor material having a plurality of activecomponents fabricated thereon, the active components including at leastone of a plurality of sensing devices or a plurality of detector devicesfabricated thereon; and a plurality of passive components formedthereon, at least some of the passive components being respectivelydimensioned and arranged to receive radiation exiting a correspondinganalyte and to direct the radiation along a path terminating at one ormore of the sensing or detector devices, wherein each passive componentcomprises at least one metallic structure dimensioned and arranged toabsorb and/or reflect a major fraction of received exiting radiation,received at one or more wavelengths of a first group of wavelengths, soas to prevent such major fraction from being one of received orprocessed by the plurality of sensing devices and/or plurality ofdetecting device. Alternatively, or in addition, the at least onemetallic structure is dimensioned and arranged to direct an amount ofreceived exiting radiation, received at one or more wavelengths of asecond group of wavelengths, sufficient to enable at least one ofreceiving or processing by the at least one of the plurality of sensingdevices or plurality of detecting devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a passive component incorporating anarray of metallic waveguides disposed within a dielectric layer,according to one or more embodiments;

FIG. 1B is a perspective view depicting an array of metallic waveguideshaving a uniform spacing and pitch and a circular cross sectionalprofile, according to some embodiments;

FIG. 1C is a perspective view depicting an array of metallic waveguidessimilar to that shown in FIG. 1B but having a hexagonal cross sectionalprofile, according to some embodiments;

FIG. 1D is a perspective view depicting an array of metallic waveguidessimilar to that shown in FIGS. 1B and 1C but having a rectangular crosssectional profile, according to some embodiments;

FIG. 2A is a perspective view of an array of metallic structuresconstructed according to one or more embodiments;

FIG. 2B is a perspective view of an array of metallic structuresobtained by conventional CMOS fabrication techniques, according to onemore embodiments;

FIGS. 3A and 3B are graphical representation of transmittance as afunction of wavelength for an illustrative sub-wavelength waveguidearray structure according to an embodiment of the present disclosure,for each of three different metals used in their fabrication;

FIGS. 3C and 3D are graphical representations of transmittance as afunction of wavelength for a illustrative sub-wavelength waveguide arraystructure according to an embodiment of the present disclosure, based onselection of copper as the metal used in their fabrication;

FIGS. 3E and 3F are graphical representations of transmittance as afunction of wavelength for a illustrative sub-wavelength waveguide arraystructure according to an embodiment of the present disclosure, based onselection of copper as the metal used in their fabrication;

FIGS. 3G and 3H are graphical representations of transmittance as afunction of wavelength for a illustrative sub-wavelength waveguide arraystructure according to an embodiment of the present disclosure, based onselection of copper as the metal used in their fabrication;

FIGS. 3I and 3J are graphical representations of transmittance as afunction of wavelength for a illustrative sub-wavelength waveguide arraystructure according to an embodiment of the present disclosure, based onselection of copper as the metal used in their fabrication;

FIGS. 3K and 3L are graphical representations of transmittance as afunction of wavelength for a illustrative sub-wavelength waveguide arraystructure according to an embodiment of the present disclosure, based onselection of copper as the metal used in their fabrication;

FIGS. 4A and 4B exemplify light of different wavelengths (780 nm and 405nm, respectively) entering a spectral filter of the type employing anarray of metallic waveguide structures according to the embodiments ofFIGS. 1A-1D, 2A, and 2B;

FIG. 4C is a graphical representation of the measured result(transmission spectrum) for a waveguide array designed and fabricated ina CMOS 65 nm process, according to one or more embodiments;

FIG. 4D is a graphical representation depicting filtering performanceagainst the emission and excitation spectra for an exemplary commercialanalyte, in accordance with a simulation of results achieved by one ormore embodiments.

FIG. 5A is a model of coupled waveguide modes supported by filteringarrangements constructed in accordance with one or more embodiments;

FIGS. 5B-5E depict distinct loss behaviors between two different kindsof modes for passive components employing an array of metallicstructures according to one or more embodiments;

FIG. 6A-6B and depict another class of metallic structures adapted forintegration with such conventional devices as detectors and imagingsensors and which may, for example, be used to implement grating anomalyfilters or other passive optical components according to one or moreembodiments;

FIGS. 6C and 6D depict FDTD simulation results for several designexamples of grating anomaly filters according to one or more embodimentsof the present disclosure;

FIGS. 7A and 7B are perspective and plan views, respectively, which showyet another class of metallic structure applicable to passive componentsadapted for integration with active semiconductor devices, utilizingmeta-material structures according to one or more embodiments;

FIGS. 7C-7E are respective plan views depicting other meta-materialstructures according to one or more embodiments;

FIG. 8A to 8D are graphical representations of filter performanceobtained using meta material structures according to embodiments of thepresent disclosure;

FIG. 9 is a cross sectional view depicting an integrated detecting,sensing or measuring system which integrates both passive and activeoptical components in a single structure, according to one or moreembodiments;

FIGS. 10A and 10B depicts schematics for an integrated photodetectorarchitecture with dark current compensation, correlated double sampling,and microscopic view of differential diode layout, with FIG. 10B furtherincluding a timing diagram, according to one or more embodiments;

FIG. 11 and FIG. 12 are graphical representations depicting The measuredspectral responsivity (405-830 nm) and the sensitivity of an integratedsensing device at an emission wavelength of around 780 nm, according toone or more embodiments;

FIG. 13A is depicts a functionalized monolithically integrated chipconstructed according to an embodiment of the present disclosure;

FIG. 13B is a schematic of a functionalized, monolithically integratedfluorescence imaging system constructed according to another embodimentof the present disclosure;

FIGS. 13C and 13D depict the separation between a sample underfluoroscopic investigation and an imaging plane, according to one ormore embodiments;

FIG. 14 is a perspective view depicting processes of chip surfacefunctionalization and affinity reaction for an antigen/antibody assay,according to one or more embodiments; and

FIG. 15 is a perspective view depicting a double chip fluorescencemicroscopy system according to one or more embodiments.

While the components and systems are described herein by way of examplefor several embodiments and illustrative drawings, it should beunderstood that the drawings and detailed description thereto are notintended to limit embodiments to the particular form disclosed. Rather,the intention is to cover all modifications, equivalents andalternatives falling within the spirit and scope of the components andsystems defined by the appended claims. Any headings used herein are fororganizational purposes only and are not meant to limit the scope of thedescription or the claims. As used herein, the word “may” is used in apermissive sense (i.e., meaning having the potential to), rather thanthe mandatory sense (i.e., meaning must). Similarly, the words“include”, “including”, and “includes” mean including, but not limitedto.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the disclosure andhow it may be practiced in particular embodiments. However, it will beunderstood that the present disclosure may be practiced without thesespecific details. In other instances, well-known methods, procedures andtechniques have not been described in detail, so as not to obscure thepresent disclosure. While the present disclosure will be described withrespect to particular embodiments and with reference to certaindrawings, the disclosure is not limited hereto. The drawings includedand described herein are schematic and are not limiting the scope of thedisclosure. It is also noted that in the drawings, the size of someelements may be exaggerated and, therefore, not drawn to scale forillustrative purposes.

Furthermore, the terms first, second, third and the like in thedescription and in the claims, are used for distinguishing betweensimilar elements and not necessarily for describing a sequence, eithertemporally, spatially, in ranking or in any other manner. It is to beunderstood that the terms so used are interchangeable under appropriatecircumstances and that the embodiments of the disclosure describedherein are capable of operation in other sequences than described orillustrated herein.

Moreover, the terms top, bottom, over, under and the like in thedescription and the claims are used for descriptive purposes and notnecessarily for describing relative positions. It is to be understoodthat the terms so used are interchangeable under appropriatecircumstances and that the embodiments of the disclosure describedherein are capable of operation in other orientations than described orillustrated herein. As used herein, the phrase major fraction isintended to refer not to a specific proportion, or even a range ofpercentage values of absorbtion and/or reflection of light, but ratherto the rejection of a sufficient amount of energy as to impede thesensing, measuring, or detection of a energy at a particular wavelengthor within a particular band of wavelengths other than those beingreflected or absorbed.

As used herein, the phrase “dimensioned and arranged for silicon deviceintegration” or “for semiconductor device integration” is intended torefer metallic components which are of a sufficiently small scale as topermit fabrication of spectral filters and other passive components madeof metal (or a metal alloys during the process of fabricating one ormore active devices within or upon a substrate of semiconductor materialas, for example, silicon, gallium arsenide, indium gallium arsenide, orindium gallium arsenic phosphide (InGaAsP). In some embodiments,portions of the metallic structures comprising the passive componentshave dimensions on the order of 100 nm or even less.

As used herein, the term “metal material” structures are intended torefer to waveguide structures utilizing a gap or “slot”, whether asdiscrete individual structures or as arrays of such individualstructures, with the terms “slotted resonators” being one examplethereof and intended to refer generically to such structures as thesplit ring resonator structures, and to “U” and “H” shaped resonatorstructures described in the present disclosure.

As used herein, the term “active component” is intended to refer tothose devices fabricated from silicon or other semiconductor materials,especially but not limited to those fabricated from low cost CMOSfabrication processes, and which are responsive to the application of acurrent or voltage to alter the flow of current or the voltage appliedto other devices in a circuit.

Described herein are passive components adapted for integration with awide range of detection, sensing, and spectroscopic imaging devices.Although examples described in detail herein are presented in thecontext of novel optical fluorescence-based chemical and biochemicalsensors and multi-analyte detection and imaging systems, such examplesare presented to highlight the applicability of low-cost materials andsimple fabrication techniques to the implementation of such systems. Inthe context of such illustrative examples set forth in this disclosure,an analyte is an element or a substance to be detected, such as a gas, avapor or a liquid.

According to some embodiments of the present disclosure, passivecomponents in the form of spectral filters and other metallic structuresare respectively constructed as part of a conventional semiconductordevice fabrication integration process such, for example, as a CMOSfabrication process. An illustrative example of a passive component 100incorporating an array A of such metallic structures is depicted in FIG.1A. The array, indicated generally at A, comprises m×n metallicwaveguides, where one or both of M and N are integers greater than one.In FIG. 1A, each of M and N are greater than 1 and these are arranged inrespective rows R₁ to R_(N). Each row, as row R₁ for example, thereforeincludes M metallic waveguides indicated generally at 102 ₁ to 102 _(m).Likewise, row R₂ includes waveguides 104 ₁ to 104 _(m), and row R_(N)includes waveguides N₁ to N_(M).

The waveguides of array A may be made of arbitrary shapes, and aresurrounded by a dielectric layer indicated generally at 106. The spacingbetween each waveguide in a row, as waveguides 102 ₁ and 102 ₂ of rowR₁, is represented by reference numeral S_(i) while the spacing betweenwaveguides an array is represented by reference numeral Sj. In periodicexamples, the spacing between waveguides is constant within each row andthe spacing between the rows is likewise constant. In such embodiments,the dimensions S_(i) and S_(j) may, but need not be, equal to oneanother. In that regard, the spacing between waveguides need not even beperiodic. In any event, dielectric layer 106 is disposed on a substrate108 which, may be an index-matching dielectric layer and/or may includeone or more active semiconductor devices fabricated in or on thesubstrate.

The spacings S_(i) and Sj are each sub-wavelength. That is, each ofS_(i) and S_(j) have a dimension which is less than the wavelength inthe dielectric layer λ₀/n, where λ₀ is the wavelength in vacuum and n isthe dielectric constant of the dielectric layer). This constraintensures that only efficiently conducted modes in the waveguide array(coupled surface plasmon polariton modes) are permitted, while the othertypes of the modes (for example, cavity modes) are cut-off. Such modepurification is especially useful for spectral filtering according toone or more embodiments.

It should be emphasized that surface plasmon polariton modes havedistinct waveguide loss for different wavelengths depending on thematerial property of both metal and dielectric, when the optical wavesare guided through the waveguide, spectral filtering function isrealized. One distinct advantage of the waveguide array for spectralfiltering is that light incident at any angle has to be converted to thecoupled surface plasmon polariton modes in order to go through theoptical structure. Therefore, for any incident angle, the spectralfiltering function is preserved.

The geometry of the sub-wavelength waveguide array can be chosen basedon the convenience of the fabrication process, while the characteristicsremain similar due to the fact that all sub-wavelength waveguide arraysshare the same physics mentioned above. Various periodic waveguidearrays with the same material (e.g., Cu) but different waveguide unitcells (square, circular, hexagonal cross section), as shown in FIGS. 1D,1B, and 1C, respectively, were simulated to demonstrate this behavior.It is also possible to design and fabricate one-dimensional (1×M)waveguide arrays as shown in FIGS. 2A and 2B (again, the spacing issub-wavelength but the array doesn't have to be periodic). In the caseof the array depicted in FIG. 2A, the filtering only exists for onepolarization (perpendicular, as shown in the figure). For the parallelpolarization, light for all wavelengths are largely rejected.

In practice, commercially available fabrication processes may requiresspecific design adaptations and conformance with rules applied to aspecific geometric configuration. This may lead to many variants of thewaveguide array as departures from the aforementioned basics structures.For example, a particular CMOS process may use leads to the designexample shown as FIG. 2B, which is a variation to the basic design asFIGS. 1A and 2A, respectively. These structures, while seeminglycomplex, possess all the physical performance characteristics applicableto the generalized cases discussed above.

In an embodiment, a periodic waveguide array utilizes waveguides havinga square cross section, as exemplified by FIG. 1D. Based on a length L₃of 2 microns, a waveguide width of 100 nm, an inter-waveguide spacing S₁of 100 nm, and a dielectric layer of SiO₂ (n˜1.5), a simulation wasperformed to determine the transmittance characteristics as a functionof material and the wavelengths making up the incident radiation (i.e.,that portion of the electromagnetic spectrum which is incident upon thewaveguides). FIG. 3A is a graphical representation of transmittance vswavelength, for each of three different materials (the upper curvecorresponding to silver, the middle curve corresponding to gold, andlower curve corresponding to copper). A similar plot, on a logarithmicscale, is depicted in FIG. 3B.

Selecting only copper for simulation purposes, waveguide arraysutilizing a periodic configuration and a circular cross section (FIG.1B), a hexagonal cross section (FIG. 1C), and a square cross section(FIG. 1D) were also simulated, in all cases using SiO₂ (n˜1.5) as thedielectric and a length (L₁, L₂ or L₃) of 2 microns. For waveguideshaving a circular cross sectional profile, a diameter D of 112.8 nm, anda spacing S₁ of 100 nm) were used, while in the case of the hexagonalcross sectional profile, the apical spacing was 76 nm and the side ofeach hexagon was 62.0 nm. FIG. 1D utilized the same parameters asdiscussed above in connection with FIG. 1D. A graphical plot oftransmittance against wavelength is shown in FIG. 3C and, on alogarithmic scale, in FIG. 3D.

The simulated transmittance spectrum for a one-dimensional arraystructure of FIG. 2A, using copper in the fabrication of the waveguidestructures, is shown in FIGS. 3E and 3F (logarithmic scale). Forpurposes of this simulation, a length L₄ of 2 microns, an infinite widthW₄, an inter-waveguide spacing (d₁=d₂) of 100 nm, and an individualwaveguide thickness of 100 nm were used. FIGS. 3K and 3L (logarithmic)also plots the angular dependency of filter performance for thisstructure, showing that the filter works for all angles of incidence,which is especially suited for fluorescence detection applications wherethe excitation light might be scattered and only obliquely entering thefilter.

In FIGS. 3G and 3H (logarithmic), there is shown the spectrum for thestructure depicted in FIG. 2B, which is denoted as having four layers(“4L”) within each waveguide structure as structures 202′₁ to 202′_(M),as well as the spectrum for the structure that only uses the metal 3 tometal 5 layers shown in FIG. 2B, this is denoted as “3L”. In thesimulation, the spacing d₄ between adjacent structures was 130 nm andthe thickness d₃ of each structure was 100 nm. Each layer containing thevias, indicated generally at V, is 167 nm, while the metal layers have athickness t₁ of 220 nm. Clearly, the “3L” is a shortened waveguide arraystructure compared to “4L”, and therefore, its filtering performance isworse than that of the “4L”, as expected—longer waveguides have betterfiltering performance, at the expense of slightly more loss at thedesirable wavelength (in this case, the long wavelength at ˜800 nm).

Simulation results for a M×N comprising multiple rows of structurescorresponding to the arrangement of FIG. 2B (not shown) is presented inFIGS. 3I and 3J (logarithmic), where M and N are each greater than 1.

FIGS. 4A and 4B exemplify light of different wavelengths (780 nm and 405nm, respectively) entering a spectral filter of the type employing anarray of metallic waveguide structures according to the embodiments ofFIGS. 1A-1D, 2A, and 2B. Comparing the two, it will be readily apparentthat the 780 nm light largely passes through (e.g., without absorptionand/or reflection) while the 405 nm is largely rejected The measuredresult (transmission spectrum) for a waveguide array designed andfabricated in a CMOS 65 nm process is shown in the FIG. 4C. Thestructure is the same as FIG. 2B. The simulated transmittances for afour-metal-layer filter (M2-M5) are −58.7 dB for 405 nm and −2.9 dB for780 nm wavelength while the measured transmittances are −57.8 dB for 405nm and −12.1 dB for 780 nm. The higher than expected propagation loss at780 nm is currently being investigated. Nonetheless, a measuredfiltering ratio of 45.7 dB is achieved with the integratednano-plasmonic filter. The filtering performance is plotted against theemission and excitation spectra (FIG. 4D) of the labeling agent Qdot 800commercially available from Life Technologies, a quantum dot which isused in DNA as well as protein assays.

A preliminary evaluation on the nanoplasmonic waveguide array system iscarried out with the two-dimensional periodic waveguide array structureshown in FIG. 2B. All coupled waveguide modes supported in the systemcan be modeled as shown in FIG. 5A and described analytically by thefollowing equations:

${{{\cos \; k_{//}\Lambda} - {{\cos \left( {k_{1}a} \right)}{\cos \left( {k_{2}b} \right)}} + {\frac{1}{2}\left( {{\frac{ɛ_{1}}{ɛ_{2}}\frac{k_{2}}{k_{1}}} + {\frac{ɛ_{2}}{ɛ_{1}}\frac{k_{1}}{k_{2}}}} \right){\sin \left( {k_{1}a} \right)}{\sin \left( {k_{2}b} \right)}}} = 0},{{for}\mspace{14mu} {TM}}$${{{\cos \; k_{//}\Lambda} - {{\cos \left( {k_{1}a} \right)}{\cos \left( {k_{2}b} \right)}} + {\frac{1}{2}\left( {\frac{k_{2}}{k_{1}} + \frac{k_{1}}{k_{2}}} \right){\sin \left( {k_{1}a} \right)}{\sin \left( {k_{2}b} \right)}}} = 0},{{for}\mspace{14mu} {TE}}$${{{Where}\mspace{14mu} k_{1}} = \sqrt{{ɛ_{1}k_{0}^{2}} - \beta^{2}}},{k_{2} = \sqrt{{ɛ_{2}k_{0}^{2}} - \beta^{2}}}$

Where, k₀ is the wave vector in vacuum, ε₁ is the dielectric constant ofthe dielectric layer, ε₂ is the dielectric constant of the metal layer,a is the width of the dielectric spacing, b is the width of the metalwaveguide, k_(//) is the parallel wave vector charactering the coupledsurface plasmon mode and β is the wave vector or propagation constant ofthe waveguide modes—which determines the loss of the waveguides for anyparticular wavelengths. Distinct behaviors between two different kindsof modes are clearly seen in FIGS. 5B-5E. The coupled surface plasmonpolariton modes, which are also the fundamental coupled TM modes, serveas the filtering mechanism of the structure—with drastically larger modeloss in short wavelength (405 nm) than in long wavelength (780 nm).However, other modes (which behave like cut-off cavity modes) showlarger mode loss for longer wavelength. These cut-off cavity modes couldbe a degradation sources for the filter, if the designed pitch of thefilter is larger than ˜300, while smaller pitch (˜200 nm) design makesthe effect negligible. This explains the function of the sub-wavelengthspacing, mentioned above.

FIG. 6A-6D depict another class of metallic structures adapted forintegration with such conventional devices as detectors and imagingsensors and which may, for example, be used to implement an opticalfilter or other passive optical component. In a CMOS embodiment, whereinthe structure 600 is configured as an on-chip grating anomaly filter,the structure comprises a plurality of two dimensional metal gratingstacks (the material is either copper or aluminum, depending on the CMOSprocess). In the illustrative embodiment of FIG. 6B, three such stacks,indicated generally at reference numerals 610, 620, and 630, are shown.

The filter of FIGS. 6A-6D is designed to reject, to a large extent,short wavelength light over a relatively small wavelength range (subjectto tuning during the manufacturing process according to the selection ofvariable design parameters) and to allow longer wavelength light to passefficiently. The filter works well particularly when the laser lightincidence is normal to the filter plane. The pitch P of eachtwo-dimensional grating in a stack (as gratings 610, 620 or 630 of FIG.6B) is determined in accordance with Wood's anomaly law, wherein

${P = {m \times \frac{\lambda_{0}}{n}}},$

Where λ₀ is the wavelength of the laser in vacuum, n is the refractiveindex where the grating is embedded (in the case of CMOS chip, ifs theoxide layer on the silicon substrate), and m is integer (m=1 istypically used). In an embodiment, the width of the grating is on theorder of from about 0.5 to 0.7 times the pitch. The grating thickness isnot as important a parameter as the pitch and width, especially forfluorescence sensing applications. Therefore, the thickness can be atthe convenience of particular fabrication process that is used.Nonetheless, these three parameters are preferably optimized based onrigorous FDTD simulations. Although FIGS. 6A and 6B suggest the stackingof three gratings in parallel, a greater or larger number of gratingsmay be employed to obtain a requisite level of the filter performance.

There are generally two ways of cascading. First, multiple same 2Dgratings can be cascaded in order to significantly enhance the laserrejection at a particular wavelength. Second, multiple two-dimensionalgratings with slightly different pitches (say, 5-10 nm difference) canbe cascaded to enhance the bandwidth of rejection. The enhancedbandwidth, in turn, allows the laser to incident within a certain angle(thus enhancing the robustness of the filter). In order for thecascading to be effective, the spacing between adjacent filter layersshould be as large as possible, practically, to be around the laserwavelength in the dielectric medium.

Several design examples are given and the corresponding FDTD simulationresults are shown in FIGS. 6C and 6D. In each of the design examples,the grating material is chosen to be copper, though a noble metal suchas gold, silver or platinum would also provide satisfactory results. Thefirst and second grating examples are single layer two-dimensionalgratings, each having a pitch of 450 nm, and 500 nm respectively. Thethicknesses of the films are both t=220 nm, the widths are W=270 nm and300 nm, respectively. The refractive index of the dielectric medium isassumed to be 1.35. The third grating is a cascaded design-two 450 nmpitch single grating layers are positioned in parallel with a spacing of1 micron. It can be seen that the 450 nm pitch grating exhibits anomalywavelength ru·mmd 650 nm, and the 500 nm pitch grating around 710 nm,which is a very desirable property (wavelength to be filtered iscontrollable). The transmission dip at the anomaly wavelength is on theorder of around 10⁻³ to 10⁻⁴. Although this is already a typical valuefound in traditional multiple-dielectric-layer-based orabsorptive-material-based filters, if cascading is applied, therejection at the anomaly wavelength is cascaded (10⁻⁶ to 10⁻⁷transmittance), as shown in the bottom of FIG. 6D. This enables highsignal-to-noise ratio in fluorescence detection applications.

FIGS. 7A and 7B are perspective and plan views which show yet anothermetallic structure 700 applicable to passive components adapted forintegration with active semiconductor devices. Like the precedingexamples, the metallic structure 700 is especially suitable for thefabrication of on-chip optical filters. The structure 700 is referred toherein as a meta-material filter and comprises an array A₇ ofmeta-material elements.

In an embodiment, the metallic structures comprising the array A₇ ofFIG. 7A are split ring resonators 702 formed from sections as sections704 a-704 d each of which separated from its nearest neighbors by a gapG. The structures of FIGS. 7A and 7B, as well as the variants depictedin FIGS. 7C-7E, have several advantages which, in certain circumstances,make it a superior choice than previously described embodiments.

Consider the performance of the waveguide array structures described inFIGS. 1A-1D, 2A, and 2B, or the stacked gratings of FIGS. 6A and 6B. Theformer have extremely good performance and are very robust in filterapplications where its wavelength limitations do not present an issue.In fluoroscopic detection and/or imaging situations, for example, thewaveguide array is only acceptable where fluorophores having anexcitation band below 600 nm and an emission band above 650 nm areapplicable. While many fluorescent quantum dots already meet thiscriteria, anomaly filter configurations using stacked gratings—asexemplified by FIGS. 6A and 6B—have greater versatility (the latter aremore versatile because the transmission dip is tunable by tuningstructural parameters). However, this structure is not as robust forstray or scattered layer excitation light.

Metallic structures of the meta-material type advantageously deliver thedesired robustness, by providing a moderate rejection of stray orscattered light robust configuration. As shown FIGS. 7A and 7B, eachelement of the array A₇ is dimensioned and arranged so that asub-wavelength structure is obtained. The spacing S₇ are separated by adimension which is generally smaller or at most comparable to thewavelength of laser acting as the excitation source.

An embodiment of a split ring resonator is shown in FIGS. 7A and 7B andconsists of four copper bars forming a square ring with 4 gaps. Thelength L₈, width D₈, gap width G, and the metal bar thickness of theresonator are tuned and optimized in simulations to provide thedesirable filter performance. The pitch of the array is generally not asimportant in terms of its effect on performance, but it is typicallychosen so that the array is closely packed.

In some embodiments, the array formed by numerous single elementscomprises a single layer. In other embodiments, a number of layers arestacked much like the multiple-layer structure used for the GratingAnomaly filter configurations of FIGS. 6A and 6B, the cascading ofmultiple layers serving to improve the filter performance with a minorpenalty in the form of slightly decreased transmission efficiency at thefluorescence wavelength. FIGS. 7B through 7E depict several otherarchitectures of the individual metallic material structures. FIGS. 7B,7C and 7E are classical split rings, while FIG. 7F is an H-shapedresonator.

One example of the filter design for use in simulating performanceutilizes the structure of FIG. 7B, which is a split ring resonator withfour gaps. The outer side length of the square is 100 nm, the inner sidelength is 70 nm (therefore, the width of the “ring” is 15 nm), the gapwidth G is 20 nm, the pitch of the array is 150 nm, and the filter isembedded in the dielectric material with a refractive index of 1.5. Thearray is single-layer. The filter performance is shown in FIG. 8A-8D. Aclear dip is shown in each of FIGS. 8A-8D within a wavelength band ofaround 720-730 nm. Although the rejection at the transmission dip ismoderate, a distinct difference from the previous Grating Anomaly Filter(FIGS. 6A-6D) in the robustness for incident laser light or lightscattered at large angles. In the Grating anomaly filter, the rejectionof normal incident laser light is very high while the rejection of theoblique incident light is not (not shown). In comparison, theMeta-material filter works well even as we utilize a dipole source tosimulate the oblique incidence, as shown FIG. 8. Therefore, in realapplications where both directly incident (thus much stronger) andscattered laser light coexist, the two types of filters can be combinedtogether to achieve an overall good performance.

A photosensor with greater than 50 dB filtering, at a given wavelength,can be advantageously realized through an integrated photonic-electronicco-design which enables the optical layers to be brought in closeaffinity to the photo detection layer. That is, the bottom via layer canbe designed to touch the silicon. Consider a high performance filter ontop of a photo-diode, which rejects light at a particular wavelength (inour case, ˜405 nm) to a very high extent (100 dB). This means anyoptical leakage that allows 1 out of 10¹⁰ photons to reach the sensorwill degrade the filter performance.

For optimal results, any stray light or leakage light induced by, forexample, any gaps sized several microns anywhere on chip near pad, chipside, etc. or by gaps as a result of DRC rules should be eliminated. Inthis regard, the photonic copper structure and electronic copper wiringsare part of a common layer, and applicable DRC rules may dictate acertain spacing between any adjacent metal layers.

According to one or more embodiments, the aforementioned issue isresolved by a “global level” metal and via layer design methodology thatcompletely isolates the sensor from stray, scattered leakage excitationlight. An embodiment of a structure integrating both passive and activeoptical components in a single structure through application of such amethodology is depicted in FIG. 9. If any gap must exist, the lowestmetal layer with via stacks is dimensioned and arranged to seal it. Thisprevents light leakage from the top gap. The backside silicon (hundredsof micron thick) offers a natural optical isolation for the photonactive region. Finally, from the side, “dummy” silicon layers (i.e.,layers which are electronically isolated from the active region plus thelowest via layers) are used to prevent any light from leaking from thesides. For a wavelength around 405 nm (filtering wavelength and thelaser excitation wavelength), a typical lateral dimension of 20 micronsis typically sufficient for the dummy silicon layer to perform thesealing function.

FIGS. 10A and 10B depicts a photo-detector circuit 1000 whichincorporates dark current compensation suitable for use wherefluorescence sensing system is designed to be performed directly on asingle chip (i.e. the filters and photo-detection circuits are embeddedmonolithically). The photo-detection circuit is designed to transfer aweak fluorescence signal to an electrical signal. Preferably, the designis sensitive, characterized by low noise, and operates effectively overa large dynamic range. The simplified arrangement shown in FIG. 10Acomprises a differential photo diode 1002, a transimpedance amplifier1004 and a correlated double sampling circuit 1006.

In an extremely low-level light detection system, dark current not onlyseverely limits the dynamic range of a fluorescence imaging or detectionsystem, but it also induces non-negligible amounts of noise. In anembodiment, this issue is addressed by designing the photo-sensitivearea of the photo diode to be divided alternatively into a plurality ofmodules—half of them form the “real” photo-detector that detects thefluorescence signal, and the other half are covered by thick metallayers to serve as a “dummy” photo diode. In operation, the dark currentin the two photo diodes should be very dose to each other, in accordancewith the differential design. In the illustrative example of FIG. 10A,the photo-sensitive areas of the photodiode are divided into eightmodules for each of the “real” and “dummy” detecting functions,respectively.

Differential transimpedance amplifier 1004 subtracts the dark current ofthe dummy photo diode from the real one, which serves to increase thedynamic range. The differential signal is further processed by thecorrelated double sampling circuits 1006 (also designed to bedifferential) for purposes of noise reduction. The output of the doublesampling circuits is sent to external analog-to-digital converters forfurther process and reading.

Each sensor site comprises of a sensing diode with the nano-plasmonicfilter and a reference diode which is optically shielded. Thedifferential diode structure is laid out in an interdigitating fashion,and current compensation circuit is introduced to reduce the influenceof dark current. This increasing the attainable integration time for lowlevel light detection. As an example, a differential diode structureused in preliminary evaluation of the circuit 1000 measures 91.4 μm×123μm. The detected signal can be amplified by a capacitive trans-impedanceamplifier, operating in feedback mode which eliminates the dependency ofcircuit's responsivity on the diode capacitance. Correlated doublesampling circuits further reduce the effect of correlated noise andoffsets.

Dark current compensation mechanisms according to one or moreembodiments are designed operate in the following manner. After avoltage reset at the diode node, the integration mode starts. Lightinduced photo-current discharges the diode capacitor that results in thevoltage change at the diode node so as to be amplified and detected.However, since the diode capacitor is always leaky, which means even ifthe diodes (both reference and real) are in absolute dark, after theswitch reset, both will discharge due to the leakage current I₁, whichresults in the voltage drop at both real and reference diode nodes. Thisvoltage drop over time eventually will render the voltage at the diodenodes below the normal operation range of the TIA at the next stage,thus limiting the maximum allowed integration time (therefore, thedetection limit). On the other hand, in the integration mode, the twoswitch transistors (switch 1 as shown in the figure) controlling thediodes are not completely turned off as any transistors will always haveleakage current I₂. This leakage current essentially charges the diodeto compensate for the aforementioned diode leakage; therefore, it canimprove the maximum integration time. If I₂<I₁, then the switch 2 isalways turned off so that the minimized leakage current will be I₁-I₂.If I₂>I₁, then the switch 2 is partially turned on (controlled by itsgate voltage), so that the voltage between the note at the middle of thetwo transistor 1 and the diode node can be controlled, this controls theleakage current from the switch 1 to diode note to below I₂ and close toI₁, therefore, the net leakage at the diode node can be minimum.

According to one or more embodiments, fully integrated CMOS on-chipfluorescence sensing and microscopy systems are implemented usingpassive components such as filters, wherein the filters are configuredas sub-wavelength waveguide arrays, waveguide anomaly filters, ormeta-material structures. These systems overcome the deficienciesassociated with traditional, nonintegrated, non-portable, bulky, andcostly fluorescence sensors and microscopes. By leveraging the low costof CMOS mass manufacturing, combining small device form factor anddesign for performance and convenience, the disclosed system serves asan extremely cost-effective and convenient way for fluorescencebio-sensing and microscopy as a point-of-care diagnostic tool for healthmonitoring and disease diagnoses.

State-of-the-art-custom CMOS imager process are mostly backsideilluminated, which removes the possibility of employing the copperinterconnects as optical components. Standard digital/RF CMOS processesdo not have validated photo-detector models.

FIGS. 11 and 12 are graphical representations of sensor responsivity andsensitivity, respectively. Preliminary measurement results withdifferent forms of diode structures (n-well/psub, p-well/n-well etc)have been carried out in a 65 nm CMOS fabrication process. A fabricatedchip with integrated nano-plasmonic filter shows the lowest measuredlight level to be 39 pW (corresponding to 6.92 fA photo current) in 780nm wavelength (where linearity of the chip response is still preserved.This comparatively lower than expected performance is due to thefollowing several factors: 1) the nano-plasmonic filter itself accountsfor a larger than 12 dB loss in the 780 nm region, 2) non-optimizeddiode structure having a much lower responsivity. If the sensitivity ofthe biosensor is limited by the emission filter and stray lightscattering, then the minimum detectable analyte is independent of the ofthe diode quantum efficiency and the common loss associated in thefilter. This is because both the excitation light and the fluorescencelight are affected by this. The measured spectral responsivity (405-830nm) and the sensitivity of the chip at the emission wavelength of around780 nm are shown in FIG. 11. As expected, the responsivity resemblesthat of the filter and 47.6 dB filtering ratio was obtained for 405 nmexcitation wavelength and 780 nm emission wavelengths. For 780 nmwavelength, highly linear response (photo current verses incidencepower) was measured over 82 dB dynamic range.

An end-end design process for a fully integrated optical biosensor withan active bio-interface requires a multi-disciplinary approach. Thisincludes preparing the interface with the bio-sample that involvesfunctionalization of chip surface (both for DNA and proteins, forexample) and sample (liquid) handling mechanism. This process has to beco-designed with the optical and electronic signal detection andprocessing.

FIG. 13A depicts an illustrative fluoroscopic detection system 1300utilizing a multiplexed chip 1302. The multiplexed chip 1302, comprisinga plurality of the individual sensors 1304 described above, isfunctionalized with different probes at different sensor locations andthe sample of interest is allowed to incubate in contact with the probe.The CMOS chip is fixed either in a chip carrier or directly on theprinted circuit board using conductive epoxy (such as silver epoxy).Then the pads of the chip are wire connected using wire bonder. All padsand wires are then protected using adhesive but non-conductive materialssuch as silicone (PDMS), this step is to prevent any conductive liquidduring the bio-assay process to short the chip by connecting differentpads or wires. After the pads and wires are protected, a liquid handlingchamber made of either glass of plastics is placed. This chamber couldeither be custom made or a ring shaped glass/plastic to hold the liquid.In the case that the chip is placed on the chip carrier then the chipcarrier on PCB, the chip carrier along with the chip, the liquidhandling chamber is used in the form of a cartridge, which can bereplaced or disposed of after the detection mechanism.

FIG. 13B depicts a monolithically integrated fluorescence imaging system1300′ constructed according to a conventional semiconductor devicefabrication technique such, for example, as CMOS processing. In theexemplary arrangement of FIG. 13B, the system 1300′ comprises an array1340 of individual copper light guides 1342, which array is dimensionedand arranged directly above an array 1350 of CMOS photo-detectors (imagesensor) 1352.

Typically, the individual pixel size of each CMOS image sensor 1352 isfrom about 2 to about 10 microns, depending on the CMOS process anddesign. The light guides 1342 are of similar dimensions. In anembodiment, each light guide is fabricated from copper and has arectangular cross sectional profile, which may or may not be a squarecross-section as suggested in FIG. 13B.

The wall thickness of each light guide 1342 is typically thin (i.e., onthe order of 100 nm). In many commercial scale CMOS fabricationprocesses, nominal dimensions such as these may hot be practical tofabricate. Modification of the design may be necessary to approximateand/or emulate an idealized “hollow waveguide”.

In a CMOS process where a via layer of 100 nm×100 nm cross section is adesign limitation, and the array pitch is likewise 100 nm,sub-wavelength metallic structures can be directly used to implementthin wall “hollow waveguide”, since the sub-wavelength designcharacteristically prevents photons in one light guide from leaking toan adjacent structure. In addition, the light guide needs to be as closeto the image sensor 1352 and bio sample as possible-the bio sample forimaging is prepared directly on the top of the chip. Nonetheless thereis still spacing between the sample and the light guide, which wouldresult in the image blurring (similar argument holds for the spacingbetween light guide and photo detector). Finally, robust optical filterssuch as the sub-wavelength copper plasmonic waveguide array andsubstrate based metamaterial filters can be directly incorporated in thelight guide. In the exemplary embodiment of FIG. 13B, a spectral filtercomprising an array of sub-wavelength copper plasmonic waveguides 1345(only one row of which is shown). The respective arrays of light guides1342, sub-wavelength copper plasmonic waveguides 1345, and sensors 1352are fabricated according to conventional CMOS techniques using, in anembodiment, a silicon-based material system. Other semiconductormaterial systems, with which spectral filters and other passivecomponents fabricated in accordance with the present disclosure areespecially adapted for integration with sensing, detecting or imagingdevices fabricated from those materials include GaAs, InP, and InGaAsPdepending upon the nature of the application.

As such, the monolithically integrated structure 1310 can directlyfunction as an imaging system. In embodiments, the spatial resolution ofan image is primarily determined by the pixel pitch, and is generally,two to three times the pitch. Since a 2-3 micron pixel pitch is commonin today's CMOS image sensor designs, a spatial resolution could be onthe order of from about four to about nine microns. This moderateresolution is believed by the inventors herein to be sufficient for manyfluorescence imaging applications.

FIGS. 13C and 13D depict the separation between a sample underfluoroscopic investigation and an imaging plane, according to one ormore embodiments. With reference to FIG. 13B, the estimation andanalysis of the effect of the spacing h between the bio sample plane(also the fluorophore plane) and the light guide array on the imagingresolution will now be described with reference to the need todistinguish between a pair of fluorophores with 3 pixels in a row, wherefluorophore F₁ and F₂ are each located within the boundary of pixel P₁and P₃, respectively.

Where h is close to zero, then almost all the radiation by fluorophoreF₁ and F₂ enters the pixel P₁ and P₃, respectively (i.e., no light iscaptured by pixel 2). This means that the two fluorophores are clearlydistinguishable (pixel P₁ and P₃ are each detecting light while pixel P₂remains dark). A more complex question is the effect of a nonzero valueof h on imaging resolution. Expressing the problem differently, if onedesires to use three pixels to distinguish two point sources, what isthe maximum h allowed?

Since the imaging resolution depends on various factors including theexact positions of the two fluorophores, assumptions can be made duringthe modeling process of the estimation. For purposes of analysis, it canbe assumed (1) that the fluorophores are isotropic point sources withequal radiation strength, (2) that the efficiency of the light guide forlight with different incident angles are essentially the same, and (3)that all the light at the end of the light guided are collected by thecon responding photo detectors underneath (no crosstalk between thelight guide and the photo detector).

Fixing the fluorophore F₁ at the center of the pixel P₁ and changing theposition of the fluorophore F₂ (within the boundary of pixel P₃), therequirement for the maximum h can be identified. The limiting criterionis set that if the total light intensity at the pixel P₂ is no more thanhalf of the total intensity at either pixel P₁ or pixel P₃, then the twofluorophores are distinguishable from one another. In the extremecondition where fluorophore F₂ is very close to the boundary of pixel P₂and P₃, h_(max) must be very close to zero, but generally, h<0.3L is asufficient condition for fluorophores at most locations.

FIG. 14 depicts the implementation of a sandwich assay protocol on thesurface of a CMOS sensor chip 1402 according to an embodiment. While thesensor could be prepared for detection of either nucleic acid orproteins, an example of an antibody/antigen detection is demonstrated inFIG. 14. In an embodiment, a 1-2 μm layer of Si_(O2) is deposited to thesilicon-nitride surface of the chip using chemical vapor deposition(CVD) method. To ensure a good deposition within a low temperature,PECVD is typically used. The deposition also reduces surface roughness.Then, a protocol for functionalization of glass surface is followed. Anepoxy surface or silianization of the Si_(O2) is prepared to allow thecapture antibody to be covalently bonded to the surface. The rest of thesurface is then blocked to minimize non-specific binding. In order toform different probes at different sensing sites, a spotter (such asthose used in the DNA microarray) is used to deposit different probes ondifferent sites.

After the functionalization and probe forming, the chip is incubatedwith the analyte of interest so that mostly the specific antigen ofinterest is captured by the surface. The rest of the solution along withthe nonspecific molecules is washed away (using the inlet and outlet ofthe liquid handling chamber) and the antigen is detected using afluorescence-labeled secondary antibody (could be the same probe on thesurface). When the assay is illuminated with an inexpensive diode laseror LED source, the light emitted from the tags is guided through thenanophotonic structures and detected by the photodetectors.

FIG. 15 is a perspective view depicting a double chip fluorescencemicroscopy system 1500 according to one or more embodiments. A designprocedure for the system 1500 includes a mechanical stage, which can becost-effectively made via techniques such as 3D printing, by which twoCMOS chips are mounted to support the bio-sample. A lower substrate(e.g., a first chip) 1502 serves as the detector array (image sensors)for microscopy, while a upper substrate 1504 (i.e., a second chip)includes a lens 1506. The upper substrate is supported by supports 1508,to which is secured a sample receiving tray 1509.

The lens 1506 works in reflection mode for imaging and magnification,with optimized design to eliminate various imaging aberrations. When thebio sample is illuminated by an external laser (not shown), thefluorescence image is reflected, magnified, and imaged by the CMOSmetallic lens to the lower substrate, and resolved and recorded by anarray of high-sensitivity photo-detectors. Since even in thisconfiguration, astray or scattered laser excitation light is ofteninevitable, a fully integrated filter as described previously is againused to keep the laser excitation signal away from the weak fluorescencesignal.

In an embodiment, the lens 1506 of fluorescence microscopy system 1500is an enhanced Fresnel lens. In some embodiments, the lens is a metallicstructure comprising either a series of concentric rings of wire, or aseries of arcuate or curved wire segments. Since wire is a commonly usedcomponent in many device fabrications processes, such lensconfigurations are inexpensive to manufacture—requiring little, to nomodification of existing semiconductor device processing and fabricatingequipment. Where an oxidizable metal such as copper, aluminum or silveris used, the lens may be encapsulated with a dear, dielectric materialindex matched to the application. Alternatively, a noble metal such asgold or platinum may be used.

Working in the reflection mode (where the light reflected from the metalwring interferes and focuses), the lens can be compatibly manufactured(no post fabrication is required), and offers compact system f01mfactor. More importantly, the CMOS nanometer-scale resolution offersunparalleled advantages to design and optimize the Fresnel lens toeliminate aberrations as much as possible. Two stages of design areproposed. First of all, the Fresnel lens is designed to have a fixedimaging feature, specifically, this means that the lens is designed inthe framework of diffraction optics so that the imaging of the centralpoint of the object is “theoretically perfect”, with no approximationsmade. Such design greatly improves the imaging quality of the Fresnellens. Furthermore, conventional aberration correction techniques can beused to further improve the imaging quality, especially formulti-wavelength imaging as well as off-axis imaging.

Light (e.g. from a laser source, not shown) is directed at the sample1510, which may be a bio-sample or a chemical sample, placed on tray1512. The light is then reflected by the sample and strikes lens 1506which, in turn, reflects that light toward the pixels of the sensorarray of lower substrate 1502 for detection, sensing and/or imagingaccording to one or more embodiments.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Many modificationsand variations are possible in view of the above teachings. Theembodiments were chosen and described in order to best explain theprinciples of the present disclosure and its practical applications, tothereby enable others skilled in the art to best utilize the inventionand various embodiments with various modifications as may be suited tothe particular use contemplated.

All examples described herein are presented in a non-limiting manner.Various modifications and changes may be made as would be obvious to aperson skilled in the art having benefit of this disclosure.Realizations in accordance with embodiments have been described in thecontext of particular embodiments. These embodiments are meant to beillustrative and not limiting. Many variations, modifications,additions, and improvements are possible. Accordingly, plural instancesmay be provided for components described herein as a single instance.Boundaries between various components are somewhat arbitrary, andparticular structures and combinations of elements are illustrated inthe context of specific illustrative configurations. Other allocationsof functionality are envisioned and may fall within the scope of claimsthat follow. Finally, structures and functionality presented as discretecomponents in the example configurations may be implemented as acombined structure or component. These and other variations,modifications, additions, and improvements may fall within the scope ofembodiments as defined in the claims that follow.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A passive component adapted for integration with at least one activesemiconductor device, comprising: at least one metallic structuredimensioned and arranged to at least one of absorb or reflect a majorfraction of incident radiation, received at one or more wavelengths of afirst group of wavelengths, so as to prevent such major fraction ofincident radiation from being one of received or processed by the atleast one active device, or direct an amount of incident radiation,received at one or more wavelengths of a second group of wavelengths,sufficient to enable receiving or processing of incident radiation,within the second group of wavelengths, by the at least one activedevice.
 2. The passive component according to claim 1, wherein the atleast one metallic structure comprises an m×n array of waveguides,wherein at least one of m or n is an integer greater than
 1. 3. Thepassive component according to claim 2, wherein the m×n array ofwaveguides has a uniform pitch.
 4. The passive component according toclaim 3, wherein a spacing between waveguides in the m×n array is lessthan 2000 nm.
 5. The passive component according to claim 1, whereineach waveguide of the array is fabricated from one of aluminum, copper,silver, gold or platinum.
 6. The passive component according to claim 2,wherein each waveguide of the array has one of a substantiallyrectangular or a substantially circular cross section.
 7. The passivecomponent according to claim 5, wherein each waveguide of the array isfabricated from copper and is dimensioned and arranged for silicondevice integration.
 8. The passive component according to claim 1,wherein the at least one metallic structure comprises a meta materialstructure.
 9. The passive component according to claim 8, wherein eachmeta material structure comprises at least one slotted resonator. 10.The passive component according to claim 1, wherein the at least onemetallic structure comprises a filter.
 11. The passive componentaccording to claim 10, wherein the filter comprises an m×n array ofwaveguides, wherein a spacing between waveguides in the array is smallerthan at least one wavelength for which a major fraction is to beabsorbed or reflected by the filter.
 12. The passive component accordingto claim 1, wherein the at least one metallic structure comprises agrating.
 13. The passive component according to claim 12, wherein thegrating is fabricated as one of aluminum, copper, gold, silver orplatinum embedded in a dielectric layer.
 14. The passive componentaccording to claim 1, wherein the at least one metallic structurecomprises a lens structure so as to direct radiation toward the at leastone active semiconductor device.
 15. The passive component according toclaim 14, wherein the lens structure comprises a plurality of metallicsections fabricated from one of aluminum, copper, silver, gold, orplatinum.
 16. The passive component according to claim 15, wherein theplurality of metallic sections comprising the lens structure areembedded in a dielectric layer.
 17. The passive component according toclaim 15, wherein the plurality of metallic sections comprise one ofrings or arcuate segments.
 18. A system, comprising: at least one activecomponent defined on a first substrate, the at least one activecomponent comprising a semiconductor device dimensioned and arranged toat least one of detect or process radiation incident thereon; and atleast one passive component defined on a substrate, the at least onepassive component including at least one metallic structure dimensionedand arranged to at least one of absorb or reflect a major fraction ofincident radiation, received at one or more wavelengths of a first groupof wavelengths, so as to prevent such major fraction of incidentradiation from being one of received or processed by the at least oneactive component, or direct an amount of incident radiation, received atone or more wavelengths of a second group of wavelengths, sufficient toenable receiving or processing of incident radiation, within the secondgroup of wavelengths, by the at least one active component.
 19. Thesystem according to claim 18, wherein the at least one passive componentand at least one active component are supported by the same substrate.20. The system according to claim 18, wherein the at least one metallicstructure comprises an m×n array of waveguides, wherein at least one ofm or n is an integer greater than
 1. 21. The system according to claim20, wherein the m×n array of waveguides has a uniform pitch.
 22. Thesystem according to claim 21, wherein a spacing between waveguides inthe m×n array is from below 2000 nm.
 23. The system according to claim20, wherein each waveguide of the array is fabricated from one ofaluminum, copper, silver, gold or platinum.
 24. The system according toclaim 20, wherein each waveguide of the array has one of a substantiallyrectangular, hexagonal, or a substantially circular cross section. 25.The system according to claim 24, wherein each waveguide of the array isfabricated from copper and is dimensioned and arranged for silicondevice integration.
 26. The system according to claim 18, wherein the atleast one metallic structure is a meta material structure.
 27. Thesystem according to claim 26, wherein the meta material structure is aslotted resonator.
 28. The system according to claim 18, wherein atleast one metallic structure of the at least one passive devicecomprises a filter.
 29. The system according to claim 28, wherein thefilter comprises a plurality of waveguides having a spacing smaller thanat least one wavelength for which a major fraction is to be absorbed orreflected.
 30. The system according to claim 18, wherein the at leastone metallic structure of the at least one passive component comprisesat least one grating structure.
 31. The system according to claim 30,wherein each grating structure is fabricated as one of aluminum, copper,gold, silver or platinum embedded in a dielectric layer.
 32. The systemaccording to claim 18, wherein the at least one metallic structure ofthe at least one passive component further includes a lens structure soas to direct radiation toward the at least one active component.
 33. Thesystem according to claim 32, wherein the lens structure comprises aplurality of metallic sections fabricated from one of aluminum, copper,silver, gold, or platinum.
 34. The system according to claim 33, whereinthe plurality of metallic sections comprising the lens structure areembedded in a dielectric layer.
 35. The system according to claim 33,wherein the plurality of metallic sections comprise one of rings orarcuate segments.
 36. A monolithically integrated fluorescence detectionsystem, comprising: a substrate of semiconductor material having one ormore active components fabricated thereon, the active componentsincluding one or more sensing devices or one more detector devicesfabricated thereon; and one or more passive components formed thereon,at least one passive component being respectively dimensioned andarranged to receive radiation exiting a corresponding analyte and todirect the radiation along a path terminating at one or more of thesensing or detector devices, wherein each passive component comprises atleast one metallic structure dimensioned and arranged to at least one ofabsorb or reflect a major fraction of received exiting radiation,received at one or more wavelengths of a first group of wavelengths, soas to prevent such major fraction from being one of received orprocessed by at least one of the plurality of sensing devices orplurality of detecting device, or direct an amount of received exitingradiation, received at one or more wavelengths of a second group ofwavelengths, sufficient to enable at least one of receiving orprocessing by the at least one of the plurality of sensing devices orplurality of detecting devices.
 37. The system of claim 36, wherein thesystem is a fluorescence imaging system and the active componentscomprise an array of imaging sensors.
 38. The system according to claim36, wherein the at least one metallic structure of at least some passivecomponents comprises an array of waveguides.
 39. The system according toclaim 38, wherein at least one of the arrays is an m and n array whereinat least one of m or n is an integer greater than
 1. 40. The systemaccording to claim 39, wherein a spacing between adjacent waveguides ineach m×n array is below 2000 nm.
 41. The system according to claim 39,wherein each waveguide of at least one array is fabricated from one ofaluminum, copper, silver, gold or platinum.
 42. The system according toclaim 38, wherein each waveguide of the at least one array has one of asubstantially rectangular, hexagonal, or a substantially circular crosssection.
 43. The system according to claim 41, wherein each waveguide ofthe least one array is fabricated from copper and is dimensioned andarranged for silicon device integration.
 44. The system according toclaim 36, wherein at least some of the metallic structures of the atleast one passive component are meta material structures.
 45. The systemaccording to claim 44, wherein each meta material structure is a slottedresonator.
 46. The system according to claim 36, wherein at least someof the metallic structures of the at least one passive component arefilters.
 47. The system according to claim 46, wherein the filterscomprise a plurality of waveguides having a smaller than at least oneincident wavelength for which a major fraction is to be absorbed orreflected by the corresponding filter.
 48. The passive componentaccording to claim 36, wherein the at least one metallic structurecomprises a grating.
 49. The passive component according to claim 48,wherein the grating is fabricated as one of aluminum, copper, gold,silver or platinum embedded in a dielectric layer.
 50. A passivecomponent adapted for integration with at least one active semiconductordevice, comprising: a metallic lens structure comprising at least one ofa plurality of circular rings or a plurality of arcuate segments, eachring or segment being disposed in a dielectric layer and beingdimensioned and arranged to redirect, by reflection, incident radiationreceived at one or more wavelengths.
 51. The passive component accordingto claim 50, wherein each of the circular rings or arcuate segments aredisposed within a single layer of dielectric material.
 52. The passivecomponent according to claim 50, wherein each of the circular rings orarcuate segments are fabricated from one of gold, silver, copper,aluminum, or platinum.